Remove css class causing capybara ambiguous match

What does this MR do?

Remove css class causing capybara ambiguous match and un-quarantines Group SAML specs.

Closes https://gitlab.com/gitlab-org/quality/nightly/issues/110

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content